1. Field of the Invention
The present invention pertains to a clutch disk, including a hub area and a plurality of friction lining elements which are supported on the hub area and arranged in sequence in the circumferential direction relative to a clutch disk rotational axis, and each of which provides at least part of an associated friction surface area. The friction lining elements are intended to make frictional contact with the associated opposing friction surface of a flywheel, a pressure plate, or the like.
2. Description of the Related Art
In conventional clutch disks, the friction lining elements are usually connected either rigidly or by way of axially elastic lining springs to the hub area of the clutch disk. This rigid connection has the result that, when, for example, there is a change in the local frictional relationships such as an increase in the coefficient of friction of the surfaces rubbing against each other, a spontaneous change in the torque transmitted or to be transmitted via the clutch can occur even though ultimately no change has been made in the force of the pressure being applied, which is determined by the release mechanism.
The object of the present invention is to design a clutch disk so that defined torque transmission conditions are still present, even when there are changes in, for example, the local frictional relationships in a friction clutch equipped with this type of clutch disk.
This object is achieved by a clutch disk, comprising a hub area and a plurality of friction lining elements, which are arranged in sequence in the circumferential direction relative to a clutch disk rotational axis and each of which makes available at least part of a friction surface area, where the friction lining elements are intended to make frictional contact with the associated opposing friction surface of a flywheel, a pressure plate, or the like.
At least one of the friction lining elements is supported on the hub area in such a way that it can move in the radial direction.
The present invention takes advantage of the relationship between the torque MK transmitted via the clutch disk or the clutch and various other parameters such as the coefficient of friction xcexc, the average friction radius r, the normal force FN between the surfaces rubbing against each other, and the number z of friction surface pairs rubbing against each other. This relationship is expressed by the following formula:
MK=xcexcxc3x97zxc3x97rxc3x97FN.
The present invention takes advantage of the fact that, for example, when there is a local change in the coefficient friction xcexc, such as an increase in xcexc, the ability to shift the friction lining elements, or at least one of them, in the radial direction to an appropriate extent, thus producing a corresponding reduction in the average friction radius r, can compensate for the increase in xcexc. The same is also true for an increase in the normal force FN, which can be induced, for example, by a local bulge in one of the opposing friction surfaces. Here, too, an increase in the normal force can be compensated by an appropriate reduction in the average friction radius r.
As already explained, it can be provided in the clutch disk according to the invention that the minimum of one friction lining element is designed so that it can shift in the radial direction in response to a change in the sliding frictional interaction prevailing between its own friction surface area and the opposing friction surface which is or can be associated with it.
In order to prevent simultaneously the occurrence of frictional vibrations, which can also be induced by local changes in the frictional relationships, at least one friction lining element can be supported on the hub area in such a way that it can move at least approximately in the circumferential direction relative to the rotational axis.
So that both the radial distance and the circumferential position can be changed in this way, the minimum of one friction lining element can be provided with the ability to pivot relative to the hub area around a pivot axis, which is essentially parallel to the rotational axis and a certain radial distance away from it. To ensure that the minimum of one friction lining element with a variable radial position is also held in a defined position under steady-state conditions, a restoring device can be provided to preload the minimum of one friction lining element relative to the hub area into a home pivot position.
When in particular account is to be taken of local changes in the frictional relationships which are not distributed over the entire friction area, then it is advantageous for the minimum of one friction lining element or a group of friction lining elements to be able to shift in the radial direction essentially independently of other friction lining elements or groups of friction lining elements.
The present invention also pertains to a friction clutch with a clutch disk according to the invention.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.